#include <stdio.h>

int main(){
	int year,month;
	scanf("%d %d", &year, &month);
	if ( month <= 12 && month >=1){
		switch (month){
			case 1:
			case 3:
			case 5:
			case 7:
			case 8:
			case 10:
			case 12:printf("31");break;
			case 2:if ((year%4==0 && year%100!=0) ||(year%400==0)){
				printf("29");	
			}else{
				printf("28");
			}break;
			case 4:
			case 6:
			case 11:
			case 9:printf("30");break;
		}
	}else{
		printf("error");
	}
	return 0;
}
